| Geographical distribution of 4x and 6x forms of Aegilops
crassa H. KIHARA, K. YAMASHITA, M. TANAKA and S. SAKAMOTO National Institute of Genetics, Misima, and Kyoto University, Kyoto, Japan Aegilops crassa is known to be distributed through Palestine, Syria, Iraq, Iran, Afghanistan and Turkestan (Eig 1929), but the respective geographical distribution of the 4x and 6x forms have not been established as yet. In our stock, however, 1 strain from Iraq revealed to be 4x, while 1 from Tashkent (Turkestan in U. S. S. R.) was 6x. As reported previously (see WIS No. 4, pages 19-20), H. Kihara and K. Yamashita joined the Kyoto University Scientific Expedition to the Karakoram-Hindukush in 1955 and they collected a considerable number of Aegilops in Afghanistan and Iran. Those materials have been grown in the experimental fields at Kyoto (Kihara Institute for Biological Research) and Misima (National Institute of Genetics) in 1956 and studied morphologically and cytologically. It was found that all the strains of Ae. crassa from Iran are 4x, while in Pulikhumri and Maimana (Afghanistan) 6x forms grew mixed together with the 4x(See Table 1 and the sketch-map on the cover). There are signifcant ecological and morphological differences between Afghan and Iranian strains : the Iranian group is recumbent and has narrow and dark green leaves, while Afghan strains are erect and have broad and light green leaves. In Kandahar, a city in the southern province of Afghanistan where no 6x was found, a new awnless 4x form was collected. From the fact that the 6x forms of Ae. crassa have been found mixed with 4x in the northern stretch of the Hindukush Range, it can be said that the 6x form originated there from a cross between 4x crassa and a 2x Aegilops species. The latter could have been Aegilops squarrosa which grows widely in those areas. Based on genome analysis, the genome constitution of 4x crassa is DMcr and that of 6x DMcr (?). If the above mentioned assumption is right, the unknown genome of 6x crassa should be D from Aegilops squarrosa. M. Tanaka obtained an amphidiploid from 4x crassa x Ae. squarrosa which is morphologically identical with 6x crassa. (Received May 1, 1957) |